HSUS Condemns the Use of Carbon Monoxide for Euthanasia of Animals in Shelters

When shelters find themselves in the position of having to euthanize an animal, it is incumbent upon them to ensure that the death is as humane as possible. The HSUS, the Association of Shelter Veterinarians, and all other national animal welfare organizations agree that direct injection of approved euthanasia drugs (referred to as Euthanasia by Injection, or EBI), by which the animal quickly loses consciousness without experiencing pain or distress, is the most humane method of euthanasia currently available. Lesser alternatives like carbon monoxide gas chambers (CO chambers), which can virtually never provide a stress and pain free death, must therefore never be used in shelter settings.

Gas chambers cannot provide humane euthanasia for shelter populations: Often the animals euthanized in shelters are old, young, ill or injured; none of these animals can be humanely euthanized in a gas chamber. Old, ill, injured or otherwise compromised animals may suffer from medical conditions that delay the effects of carbon monoxide, causing them to experience distress prior to unconsciousness. Neonatal animals are resistant to hypoxia and can survive much longer without oxygen than adults, making the use of inhalants such as carbon monoxide ineffective. Some small mammal species such as rabbits and guinea pigs share this quality, making them inappropriate for gas chamber euthanasia regardless of their age. Even healthy adult dogs and cats will suffer stressed just by being placed in the dark, unfamiliar environment of a gas chamber, and may become panicked by the sights, sounds and smells of the equipment and the presence of other animals. For these reasons, CO chambers cannot be relied upon to consistently produce a humane euthanasia for shelter animals, and their use cannot be condoned.

CO Chambers Pose Grave Dangers to Staff: A common fallacy is that the use of CO chambers is safer for staff members than euthanasia by injection because it avoids direct handing of animals and is more palatable than directly administering a fatal drug. In fact, the opposite is true – the use of CO chambers actually poses greater physical and psychological harm to staff. Staff must still handle, transport and place fractious and fearful animals into the CO chamber, and as such are at risk of bites and scratches. Even otherwise friendly, tractable animals may react adversely when forced into a small, dark, confined space like a CO chamber. Moreover, there is no evidence that euthanasia-related psychological stress is any less prevalent in caretakers euthanizing with a CO chamber than with EBI; if anything, staff report their stress is greater when the chamber is used instead of EBI. Even the use of the CO chamber equipment itself poses a grave risk to caretakers, as animal care workers have been injured and killed by carbon monoxide.

CO Chambers are More Costly: A CO chamber must be commercially manufactured and properly equipped and maintained or its operation will be painful and inhumane even for healthy adult dogs and cats. Studies have proven that it is actually more expensive to operate a CO chamber within the strict operational parameters required than it is to purchase and use approved euthanasia drugs.

To date, 19 states (AL, AZ, AR, CA, DE, FL, GA, IL, LA, ME, MD, NJ, NM, NY, OR, RI, TN, VA and WV) have already banned gas chambers. In 15 states (AK, CO, IN, KY, MI, NE, NC, NV, OH, OK, SC, TX, VT, WA and WY) the gas chamber is not banned outright, but shelters have the legal authority to acquire and use euthanasia drugs (referred to as “direct licensing”), so eliminating their chambers is a shelter policy choice. In the remaining 16 states, shelters have no authority to acquire euthanasia drugs directly, they must rely on the cooperation of a local veterinarian to provide them. Thankfully, there are relatively few shelters remaining in these states that are not able to acquire the drugs they need.

For the reasons cited above, when euthanasia must be performed in a shelter setting, EBI is the only acceptable humane method. In states where shelters have the ability to acquire euthanasia drugs directly, all shelters still using a CO chamber should convert to EBI immediately. Where direct licensing is not yet available, The HSUS will partner with the Humane Society Veterinary Medical Association (HSVMA) in an effort to help shelters secure access to euthanasia drugs until a direct licensing measure is passed. The HSUS will provide necessary training and assistance to any shelter committed to converting from use of a CO chamber euthanasia to EBI.